Boojum reflector: Difference between revisions
MathAndCode (talk | contribs) Added and explained a different type of boojum shuttle |
MathAndCode (talk | contribs) Corrected loop period |
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|pname = p225Boojumshuttle | |pname = p225Boojumshuttle | ||
|position = center | |position = center | ||
|viewerconfig = #C [[ AUTOSTART GPS 20 LOOP | |viewerconfig = #C [[ AUTOSTART GPS 20 LOOP 225 WIDTH 840 HEIGHT 560 ]] | ||
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Revision as of 04:18, 11 December 2020
| Boojum reflector | |||||||||
| View static image | |||||||||
| Pattern type | Stable reflector | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Number of cells | 60 | ||||||||
| Bounding box | 44 × 32 | ||||||||
| Angle | 180° | ||||||||
| Repeat time | 202 | ||||||||
| Discovered by | Dave Greene | ||||||||
| Year of discovery | 2001 | ||||||||
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The boojum reflector is a 180° glider reflector found by Dave Greene in April 2001, winning $100 bounties offered by Alan Hensel and Dieter Leithner. The name is taken from Lewis Carroll's The Hunting of the Snark, referring to the fact that a small 90-degree stable reflector was really what was wanted.[note 1]
The boojum reflector was both the smallest and fastest known stable reflector, until it was superceded by the rectifier in 2009 and the Snark in 2013.
The boojum reflector produces an unwanted beehive, which is then deleted by a later glider. If the beehive is removed before the latter glider hits it, the glider will leave the reflector. This reaction can be seen in this p226 glider shuttle:
| (click above to open LifeViewer) RLE: here Plaintext: here |
A different type of Boojum shuttle is possible by switching the output gliders and the beehive deleting gliders. The corresponding beehive-glider collision does not become nothing by itself, so a catalyst is required to delete it, but the block from that boojum suffices.
| (click above to open LifeViewer) RLE: here Plaintext: here |
Notes
- ↑ 180-degree reflectors are relatively undesirable and have limited use in larger circuitry constructions because they cannot get a glider to wherever it needs to be.
External links
- Boojum reflector at the Life Lexicon